I've heard ''me & my friend'' used many times in real life & never heard ''my friend & I'' used, sometimes grammar has to step aside for realism.

Just because people choose to speak incorrectly most of the time (myself included more than I care to admit) does not mean it's correct nor does it mean correct grammar must step aside as if it doesn't exist. When incorrect: grammar (me & my friend, etc.); spelling (luv, etc.) and word usage (to for two, your for you're, etc.) are excessively used, it gives the impression that the person is illiterate/uneducated which, in most cases, is not true. Most people go to school. I won't believe that schools teach improper spelling, grammar and word usage but I do believe each person makes his/her own choice to/not to use their knowledge. Unfortunately, much of the decision used is due to peer pressure...to be part of the crowd.

I use the "me and my friend" and "my friend and I" differing usage to determine if someone is literate or not. I don't see grammar changing for changing times on this but I do see an increasing number of people who basically aren't literate.